BACKGROUND AND AIMS Comprehensive community initiatives (CCI) aimed at reducing or preventing alcohol or other drug (AOD) harms incorporate multiple initiatives delivered to whole communities to effect community-level change on sociocultural and environmental factors. CCIs have gained in popularity and have been subject to extensive research; however, CCIs comprise multiple initiatives and evidence for effectiveness by substance type has been mixed. This umbrella review aimed to synthesise information from published reviews to describe the combination of CCIs with the most consistent evidence for impact for each substance type.

METHOD We searched Embase/Medline, PsycINFO, Cochrane Database of Systematic Reviews, two online registries and hand searched references for English language reviews without date restriction and conducted an umbrella review using mixed methods synthesis (PROSPERO CRD42023432567). We considered all types of reviews focused on CCIs and addressing AOD use or harms. Two reviewers independently screened all articles and conducted full text review. Extraction of main results relating to CCI impact and quality assessment using AMSTAR-2 and SANRA was completed by two independent reviewers and corrected covered area analysis conducted.

RESULTS We identified 87 reviews spanning three decades; 14 were rated high quality. Most reviews considered individual substances [alcohol (43 reviews) or tobacco (35 reviews) and rarely illicit drugs (16 reviews)], and some limited scope to 'at-risk' community members [young people (26 reviews) and First Nations (8 reviews)]. Although the evidence did not meet criteria for consistent impact, communities should consider implementing school-based (supported by 36 of 50 reviews) and parenting-related (29 of 37 reviews) activities that are supported by media campaign where feasible (29 of 51 reviews). CCIs have the most consistent impact on alcohol (supported by 24 of 32 reviews) and tobacco-related outcomes (22 of 35 reviews), though illicit drugs are yet to be adequately assessed.

CONCLUSIONS Although the available evidence regarding comprehensive community initiatives is largely inconsistent, the addition of parenting-related activities to existing school-based education campaigns is likely to improve effectiveness. A media campaign may extend their reach to those outside school settings. Future evaluation of CCIs should measure impact of activities in isolation where possible and incorporate process measures to gauge community engagement and empowerment.